The new Aprilaire # 58 automatic humidifier control works in conjunction with your furnace to control the operation of the humidifier. The control senses indoor RH and outdoor temperature and automatically adjusts the operation time of the humidifier to provide the optimum humidity level in the home. The digitial readout on the control displays the RH level inside the cold air return. Can also be used in manual mode when it is not possible to run wire to outdoor sensor. MOUNTS ON RETURN DUCTWORK

NOTE: control must be continously powered for proper functionality - separate 24 volt transformer may be required.

In order for the humidifier to operate, the furnace blower must be running and the humidifier control must be calling for humidity. There are several different ways to detect blower operation - see installation instructions for details. 24 VAC is also required between W/G and Cf terminals. See support addendum for details.

I bought this to replace my failing Aprilaire #56 humidistat. After doing some homework and contacting a local heating/cooling shop, I found out that the #56 model was garbage to begin with and nobody even stocks them anymore. So I decided to upgrade to the #58. I was happy to see that eventhough this humidistat has a nice display, they didn't raise the price from what they were charging for my old broken one. Installation was not to big of a deal since I was replacing an old one. The only big difference is that this unit requires a constant 24v source whereas the old one did not. To make it work I had to go down to my local electical supplier and buy a 120v to 24v converter (about $20) and wire it in off of the incoming power to the furnace blower area. I was thinking I needed this "special converter" but it turns out that the converter is the same voltage as a door bell converter...go figure. I've been using this for about 2 months now and it seems to be working nicely.

I purchased the April Air 600A a couple months ago. Although pretty much a straight forward install, You will have to do some measuring,have some sheetmetal cutting tools, and be comfortable with running some electrical from the humidistat to your hvac unit. After a couple adjustments to get the humidity level where we wanted, we ran the unit with no problems for the remainder of the heating season. As for the automatic control, I would definately get it. That way you don't have to mess with having to re-adjust your settings every time the weather changes.It definately works well. After a couple days, the humidity level came up in our house and we stopped getting shocked by everything we touched.

The new Aprilaire # 58 automatic humidifier control works in conjunction with your furnace to control the operation of the humidifier. The control senses indoor RH and outdoor temperature and automatically adjusts the operation time of the humidifier to provide the optimum humidity level in the home. The digitial readout on the control displays the RH level inside the cold air return. Can also be used in manual mode when it is not possible to run wire to outdoor sensor. MOUNTS ON RETURN DUCTWORK

NOTE: control must be continously powered for proper functionality - separate 24 volt transformer may be required.

In order for the humidifier to operate, the furnace blower must be running and the humidifier control must be calling for humidity. There are several different ways to detect blower operation - see installation instructions for details. 24 VAC is also required between W/G and Cf terminals. See support addendum for details.